SDgoods Posted September 27, 2013 Author Share Posted September 27, 2013 Can any other symptom or engine condition cause the cas to throw a code? Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted October 10, 2013 Share Posted October 10, 2013 If you look at the service manual for turbo z cars, most "change modes" at or around 3500rpms. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted October 11, 2013 Share Posted October 11, 2013 I've had issues in the past where the car would just go lean and start popping over I want to say 3500rpm, this was on stock L28ET harness/ecu/afm. Turned out to just be the crappy connection at the ECU. With the car idling try shaking your wiring harness, I have had a RELENTLESS amount of problems with the harness. Pins 28 and 36 are 2 main ground wires that run a couple inches into a crimped connector that then separates into a ground and connects to a rather large aluminum shielding wire. These are the primary grounds for the knock sensor and the CAS. This also ties into the O2 shielding. Also, I skimmed the thread, but make sure you don't have the L28ET knock sensor hooked up. As from what I've read it's not really compatible with the Z31 and will more than likely cause issues rather than helping the ECU to detect knock. Check your wires at the CAS on both sides. A friend's car we couldn't figure out why it wouldn't start. The CAS had a bunch of butt splices on it's wiring. Turns out one of them was barely making a connection. Once we soldered the connections together properly the car suddenly would fire. Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted October 13, 2013 Share Posted October 13, 2013 Any updates? Quote Link to comment Share on other sites More sharing options...
SDgoods Posted October 15, 2013 Author Share Posted October 15, 2013 I've had issues in the past where the car would just go lean and start popping over I want to say 3500rpm, this was on stock L28ET harness/ecu/afm. Turned out to just be the crappy connection at the ECU. With the car idling try shaking your wiring harness, I have had a RELENTLESS amount of problems with the harness. Pins 28 and 36 are 2 main ground wires that run a couple inches into a crimped connector that then separates into a ground and connects to a rather large aluminum shielding wire. These are the primary grounds for the knock sensor and the CAS. This also ties into the O2 shielding. Also, I skimmed the thread, but make sure you don't have the L28ET knock sensor hooked up. As from what I've read it's not really compatible with the Z31 and will more than likely cause issues rather than helping the ECU to detect knock. Check your wires at the CAS on both sides. A friend's car we couldn't figure out why it wouldn't start. The CAS had a bunch of butt splices on it's wiring. Turns out one of them was barely making a connection. Once we soldered the connections together properly the car suddenly would fire. Thanks for the input... Ill check the ECU grounds. The car starts and drives its just a couple spot along the RPM band and a Any updates? Well I swapped out 4 of the injectors ( 2 of the injectors I got sent leaked out of the body and I had to use 2 old ones) and I can go full throttle now and keep decent AFR's. But if I let the revs climb slowly it still leans out at the same spot. It will also sometimes either run pig rich (rich off the wideband) or super lean (lean off the wideband) at around 2000 rpm. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted October 16, 2013 Share Posted October 16, 2013 unplug the 02 sensor and drive the car again to see if it makes a difference. Quote Link to comment Share on other sites More sharing options...
SDgoods Posted October 24, 2013 Author Share Posted October 24, 2013 (edited) Well I got my hands on a pallnet fuel rail as i simply wanted to clean up the engine bay. Turns out it fixed my slow rpm rise issue! It still slightly misses in some areas sometimes but the stock rail must have been holding it back! I also fiddled with my make shift harness for the crank angle sensor that i partially suspected before and it seemed to affect it as well... Too bad i cant find anyone who will sell me just that portion of the harness. I think it may be causing the random missing. Its not terrible thoug and the car runs significantly better. With the stock rail if i ran fuel pressure per fsm it would be too lean under boost but fine everywhere else. With the new rail i can run it at spec and still be fine under most situations, although its still rich cruising around but better than before Edited October 24, 2013 by SDgoods Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted October 25, 2013 Share Posted October 25, 2013 Good to hear you fixed it! Quote Link to comment Share on other sites More sharing options...
JSM Posted October 25, 2013 Share Posted October 25, 2013 So you have a Z31 harness or a L28ET harness? Quote Link to comment Share on other sites More sharing options...
SDgoods Posted October 25, 2013 Author Share Posted October 25, 2013 (edited) So you have a Z31 harness or a L28ET harness? 81 ET harness with z31 ecu/maf/cas and associated connectors. Edited October 25, 2013 by SDgoods Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted October 26, 2013 Share Posted October 26, 2013 do you have an air/fuel gauge? What are your readings? I just moved my MAF another 5 inches away from the turbo, also unplugged the O2 sensor. My cruising runs 15 to 16.4 a/f reading my O2 sensor for that gauge is 28 inches from motor. My issue is mainly idling that it creeps up over 18 out of scale. Smells real rich but is showing lean. Quote Link to comment Share on other sites More sharing options...
DuoWing Posted October 26, 2013 Share Posted October 26, 2013 For the crank angle sensor, I was lurking over on Z31Performance and apparently just about any VG30 vehicles with a PRW-2/a ignitor has a newer version of the CAS in their distributors, that you just have to remove some locating pins on and these will fit in our distributors, also they use the same style harness connector to the CAS. You may have to change the way it connects to the harness itself, but this way you can go to a junkyard and pull a CAS/connector for it from older Nissans, but primarily Nissan Quest/Mercury Villager Vans up to 1998 Quote Link to comment Share on other sites More sharing options...
NewZed Posted October 26, 2013 Share Posted October 26, 2013 (edited) Well I got my hands on a pallnet fuel rail as i simply wanted to clean up the engine bay. Turns out it fixed my slow rpm rise issue! It still slightly misses in some areas sometimes but the stock rail must have been holding it back! ......... With the stock rail if i ran fuel pressure per fsm it would be too lean under boost but fine everywhere else. With the new rail i can run it at spec and still be fine under most situations, although its still rich cruising around but better than before Seems more likely that you knocked some wires around when you were swapping rails, or the stock rail was damaged. The stock rail should flow plenty of fuel unless it had a bad dent or crimp in the tubes from being removed and replaced many times. Or you had a bad FPR and that was swapped along with the rail. Something's not right about your solution. (Sorry Pallnet, this post was probably worth 10 sales). Edited October 26, 2013 by NewZed Quote Link to comment Share on other sites More sharing options...
SDgoods Posted October 27, 2013 Author Share Posted October 27, 2013 Seems more likely that you knocked some wires around when you were swapping rails, or the stock rail was damaged. The stock rail should flow plenty of fuel unless it had a bad dent or crimp in the tubes from being removed and replaced many times. Or you had a bad FPR and that was swapped along with the rail. Something's not right about your solution. (Sorry Pallnet, this post was probably worth 10 sales). Nothing else changed. I suppose its possible the injector wiring could have had an issue and I moved it around, but I already had an aftermarket regulator on there. If you read the previous comments, when I swapped some of the injectors out I was able to go full throttle even with the stock rail. It was still cutting out around 3500 under partial throttle though. Now It revs fine no matter the throttle input although it does have a slight misfire in some spots. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.